Artificial turf system

ABSTRACT

An artificial turf system for installation over a receiving surface. The artificial turf system comprising: a sheet member made of a flexible material, the sheet member defining a first surface for interfacing with the receiving surface and a second surface; primary yarns made of straight fibers backstitched in and threaded through the sheet member and upwardly extending from the sheet member to a first elevation; and secondary yarns made of textured fibers backstitched in and threaded through the sheet member and upwardly extending from the sheet member at a second elevation less than the first elevation which is caused by a difference in texture between the primary yarns and the secondary yarns, wherein the secondary yarns are more rigid than the primary yarns, and wherein the primary yarns and the secondary yarns have ends which are cut after being threaded through the sheet member.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority from U.S. patent application Ser. No.15/065,138 filed Mar. 9, 2016, which claims priority from U.S. patentapplication 62/130,113 filed Mar. 9, 2015, the specification of whichare hereby incorporated herein by reference in their entirety.

BACKGROUND (A) Field

The subject matter disclosed generally relates to playing fields andmore particularly to artificial sports and amusement playing fields. Thesubject matter disclosed may also relate to artificial turf surface ofall kinds (i.e., artificial sports playing fields, artificial amusementplaying fields, gymnasium surfaces, backyard surfaces and the like).

(b) Related Prior Art

The use of artificial or synthetic turf has been growing steadily inrecent years. Artificial turf is a surface of synthetic fibers made tolook like natural grass. It is most often used in arenas and fields forsports that were originally or are normally played on grass.

However, it is now being used in other applications such as, forresidential lawns or landscapes, for pet areas, for child playgrounds,for golf courses and putting greens, on roofs, decks and patios as well.

The advantages of synthetic turf are numerous. For example, syntheticturf does not need to be cared as much as real grass. Moreover,synthetic turf is more durable.

There exist on the market numerous artificial or synthetic turf systemsaiming to provide improved comfort, sufficient traction, and shockabsorbent characteristics. For example and now referring to PRIOR ARTFIGS. 1A and 1B, there is shown a regular artificial turf system 10which includes a sheet member 12 made of a flexible material and aplurality (substantially straight) fibers 14 upwardly extending from thesheet member 12. The plurality of fibers 14, which creates a carpet-liketop layer, therefore includes a series of regularly spaced apart (orequally spaced) parallel rows of backstitches 16. For providing theshock absorbent characteristic, straight fiber support and sufficienttraction for the desired sport to the artificial turf system 10, aplurality of rubber granules and/or sand (not shown, such as fromrecycled tires) are often disposed on the artificial turf system 10.

Even though the rubber granules and/or sand used in modern artificialsynthetic turf tend to contain lower quantities of harmful substances,such as metal (e.g., lead and zinc), inorganic and organic compounds, itmay significantly increase health problems for those playing/walking onit, it may significantly increase the surface temperature above thesurface covering panel and it may lead to some other environmentalproblems. The infill also becomes compacted with time affecting directlyshock absorption and traction of the artificial synthetic turf to thedetriment of the players.

As for another example and referring now to PRIOR ART FIGS. 2A and 2B,there is shown an artificial turf system without infill 100 forinstallation over a receiving surface (not shown). The artificial turfsystem 100 includes a sheet member 102 made of a flexible material. Thesheet member 102 defines a first surface or primary backing 104 forinterfacing with the receiving surface and a second surface 106. Theartificial turf system 100 further includes a plurality of primary yarns108 made of straight fibers (monofilament, parallel fibrillated orfibrillated fibers) which are upwardly extending from the second surface106 of the sheet member 102 and a plurality of secondary yarns 110 madeof textured fibers or thatch fibers which are upwardly extending fromthe second surface 106 of the sheet member 102. The plurality ofsecondary yarns 110 are positioned on the sheet member 102 such as tointersperse with the plurality of primary yarns 108.

The plurality of secondary yarns 110 made of textured or thatch fibersrepresent less than 50% in weight (aka face weight) of the plurality ofprimary and secondary yarns 108, 110 taken together. Therefore, thestraight fiber support, traction and shock absorbent characteristics arenot optimized.

The plurality of primary and secondary yarns 108, 110 which createstogether a carpet-like top layer 112 includes a series of regularlyspaced apart (or equally spaced) parallel rows of backstitches 114, 116tufted or knitted in straight line, in “zigzag” or in a S pattern. Theseries of regularly spaced apart parallel rows of backstitches 114, 116include a series of regularly spaced apart parallel rows of backstitches114 made of the plurality of primary yarns 108 and a series of regularlyspaced apart parallel rows of backstitches 116 made of the plurality ofsecondary yarns 110, which are interspersed within the series ofregularly spaced apart parallel rows of backstitches 114 made of theplurality of primary yarns 108.

The fact that the artificial turf system 100 combines both the pluralityof primary yarns 108 made of straight fibers and the plurality ofsecondary yarns 110 made of textured or thatch fibers provides straightfiber support and player traction to the artificial turf system 100.However, according to this configuration, the straight fiber support,players traction and shock absorbent characteristic are not optimized.

There is therefore a need for improved non infilled artificial turfsystem that optimizes straight fiber support, player traction and shockabsorbent characteristics and that would overcome the above-noteddrawbacks.

SUMMARY

According to an embodiment, there is provided an artificial turf systemfor installation over a receiving surface, the artificial turf systemcomprising: a sheet member made of a flexible material, the sheet memberdefining a first surface for interfacing with the receiving surface anda second surface; primary yarns made of straight fibers backstitched inand threaded through the sheet member and upwardly extending from thesecond surface of the sheet member to a first elevation; and secondaryyarns made of textured fibers backstitched in and threaded through thesheet member and upwardly extending from the second surface of the sheetmember at a second elevation less than the first elevation defining adifference in elevation which is caused by a difference in texturebetween the primary yarns and the secondary yarns, wherein the secondaryyarns are more rigid than the primary yarns, and wherein the primaryyarns and the secondary yarns have ends which are cut after beingthreaded through the sheet member.

According to an aspect, the material used for the primary yarns is notthe same material which is used for the secondary yarns, wherein thematerial used for the secondary yarns is more rigid than the materialused for the primary yarns.

According to an aspect, the secondary yarns are textured, and whereinthe textured fibers comprise crimped fibers.

According to an aspect, the secondary yarns represent more than 50% inweight of the primary and secondary yarns together.

According to an aspect, combined yarns composed of the primary andsecondary yarns are backstitched in parallel equally spaced apart rowson the sheet material.

According to an aspect, the mass of the secondary yarns is greater thanthe mass of the primary yarns.

According to an aspect, the mass of the secondary yarns is in a rangebetween 15,001 and 20,000 deniers.

According to an aspect, the primary yarns and the secondary yarns haverespectively a length, and wherein the length of secondary yarns isgreater than the length of primary yarns.

According to an aspect, a ratio of the second elevation over the firstelevation is smaller than 75%.

According to an embodiment, there is provided an artificial turf systemfor installation over a receiving surface, the artificial turf systemcomprising: a sheet member made of a flexible material, the sheet memberdefining a first surface for interfacing with the receiving surface, anda second surface; a plurality of primary yarns being backstitched to thesheet member at primary backstitches, with the primary yarns raisingfrom the primary backstitches away from the second surface to a firstelevation; and a plurality of secondary yarns defining an underturf, thesecondary yarns being backstitched to the sheet member at secondarybackstitches, wherein the secondary backstitches are distributedin-between the primary backstitches, wherein the secondary yarns extendfrom the secondary backstitches up to a second elevation lower than thefirst elevation, wherein the secondary yarns extend sideways in randomdirections, and wherein the secondary yarns intertwine with othersecondary yarns.

According to an aspect, the primary yarns comprise a lower sectionrising from the sheet member under the second elevation, and wherein theunderturf provides a least partial support to the lower section of theprimary yarns thereby impeding the lower section of the primary yarnsfrom curving, bending or crooking.

According to an aspect, the primary yarns are made of straight fibers.

According to an aspect, the secondary yarns are made of curved fibers.

According to an aspect, the plurality of secondary yarns represents morethan 50% in weight of the sum of the plurality of primary and secondaryyarns together.

According to an aspect, the secondary yarns are more rigid than theprimary yarns.

According to an aspect, the secondary yarns are textured, and whereinthe textured fibers comprise crimped fibers.

According to an aspect, the primary yarns and the secondary yarns haverespectively a length, and wherein the length of secondary yarns isgreater than the length of primary yarns.

According to an aspect, a ratio of the second elevation over the firstelevation is smaller than 75%.

According to an aspect, the primary yarns and the secondary yarns haverespectively a width, and wherein the width of the primary yarns isgreater than the width of the secondary yarns.

According to an aspect, the primary yarns and the secondary yarns haverespectively a thickness, and wherein the thickness of the secondaryyarns is equal or greater than the width of the primary yarns.

According to an embodiment, there is provided an artificial turf systemfor installation over a receiving surface. The artificial turf systemcomprises a sheet member made of a flexible material, the sheet memberdefining a first surface for interfacing with the receiving surface anda second surface. The artificial turf system further comprises aplurality of primary yarns made of straight fibers upwardly extendingfrom the second surface of the sheet member and a plurality of secondaryyarns made of textured fibers upwardly extending from the second surfaceof the sheet material and interspersed within the plurality of primaryyarns. The plurality of secondary yarns represent more than 50% inweight of the plurality of primary and secondary yarns together.

According to an aspect, the plurality of secondary yarns are made oftextured, thatched or crimped fibers.

According to another aspect, the primary and secondary yarns arebackstitched in parallel equally spaced apart rows on the sheetmaterial.

According to another aspect, combined yarns composed of the primary andsecondary yarns are backstitched in parallel equally spaced apart rowson the sheet material.

According to another aspect, the artificial turf system with combinedyarns composed of the primary and secondary yarns are backstitched inparallel equally spaced apart rows on the sheet material, with the rowsforming a straight, S, or Z pattern.

According to another aspect, the artificial turf system with combinedyarns composed of the primary and secondary yarns are backstitched inparallel equally spaced apart rows on the sheet material, with adistance separating two rows being ranged between 1/16″ and ½″.

According to another aspect, the sheet material is manufactured as oneof a closed-weave woven, an opened-weave woven, leno weave cross weaveor non-woven material.

According to another aspect, the thickness of the sheet member issubstantially uniform and ranges between 0.20 mm to 2 mm.

According to another aspect, the mass of each of the plurality ofprimary yarns is ranged between 2,000 and 20,000 deniers.

According to another aspect, the plurality of secondary yarns are madeof textured, thatched or crimped fibers and the mass of each of theplurality of secondary yarns is ranged between 2,000 and 20,000 deniers.

According to another aspect, the plurality of primary and secondaryyarns are bound to the sheet member by heat, pressure or withPolyurethane.

According to another aspect, the primary yarns have a first length, thesecondary yarns have a second length, and the second length is at leastequal to the first length.

According to another aspect, the plurality of secondary yarns made oftextured or thatch fibers represents one of: more than about 51%, morethan about 55%, more than about 60%, more than about 65%, more thanabout 70%, more than about 75%, more than about 80%, more than about85%, more than about 90% and more than about 95% in weight of theplurality of primary and secondary yarns together.

According to another aspect, at least one of a material in which is madethe secondary yarns and a process performed on the secondary yarnsrender the secondary yarns more rigid than the primary yarns.

According to another aspect, the primary yarns are made of one ofpolyethylene, polypropylene, Polyamide, polyester (PET), and acombination of polyethylene and polypropylene.

According to another aspect, the secondary yarns are made of one ofPolyamide, Polyester (PET), polyethylene, polypropylene, and acombination of polyethylene and polypropylene.

According to another aspect, the elevation of the secondary yarns withrespect to the second surface is less than the elevation of the primaryyarns with respect to the second surface.

According to another embodiment, there is provided an artificial turfsystem for installation over a receiving surface. The artificial turfsystem comprises a sheet member made of a flexible material, the sheetmember defining a first surface for interfacing with the receivingsurface and a second surface. The artificial turf system furthercomprises a plurality of primary yarns made of substantially straightfibers upwardly extending from the second surface of the sheet memberand having a first elevation with respect to the second surface, and aplurality of secondary yarns upwardly extending from the second surfaceof the sheet material, the plurality of secondary yarns having a secondelevation, lesser than the first elevation, with respect to the secondsurface. The artificial turf system has the plurality of primary andsecondary yarns backstitched to the sheet material such as eachbackstitch is composed of a plurality of secondary yarns surrounding atleast one primary yarn.

According to a further embodiment, there is provided an artificial turfsystem for installation over a receiving surface. The artificial turfsystem comprises a sheet member made of a flexible material, the sheetmember defining a first surface for interfacing with the receivingsurface and a second surface. The artificial turf system furthercomprises a plurality of primary yarns made of substantially straightfibers upwardly extending from the second surface of the sheet memberand having a first elevation with respect to the second surface, and aplurality of secondary yarns upwardly extending from the second surfaceof the sheet material and interspersed within the plurality of primaryyarns, the plurality of secondary yarns having a second elevation,lesser than the first elevation, with respect to the second surface. Theplurality of secondary yarns represent more than 50% in weight of theplurality of primary and secondary yarns together.

Features and advantages of the subject matter hereof will become moreapparent in light of the following detailed description of selectedembodiments, as illustrated in the accompanying figures. As will berealized, the subject matter disclosed and claimed is capable ofmodifications in various respects, all without departing from the scopeof the claims. Accordingly, the drawings and the description are to beregarded as illustrative in nature, and not as restrictive and the fullscope of the subject matter is set forth in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the present disclosure will becomeapparent from the following detailed description, taken in combinationwith the appended drawings, in which:

FIG. 1A is a schematic showing the top surface of an infilled artificialturf system in accordance with the PRIOR ART;

FIG. 1B is a schematic showing the bottom surface of the infilledartificial turf system in accordance with the PRIOR ART;

FIG. 2A is a schematic showing the top surface of a non infilledartificial turf system in accordance with the PRIOR ART;

FIG. 2B is a schematic showing another side (perpendicular to the sideshown in FIG. 2A) of the non infilled artificial turf system of FIG. 2Ain accordance with the PRIOR ART;

FIG. 3 is a schematic showing the top surface of an artificial turfsystem in accordance with an embodiment;

FIG. 4 is a schematic showing the side of the artificial turf system ofFIG. 3;

FIG. 5 is a schematic showing a close-up view of the artificial turfsystem of FIG. 3;

FIG. 6 is a schematic showing the bottom surface of the artificial turfsystem of FIG. 3; and

FIG. 7 is a schematic showing a close-up view of the sheet member of theartificial turf system.

It will be noted that throughout the appended drawings, like featuresare identified by like reference numerals.

DETAILED DESCRIPTION

In embodiments, there are disclosed artificial turf systems for applyingon receiving surfaces.

Referring now to the drawings, and more particularly to FIGS. 3-6, thereis shown a non infill artificial turf system 200 for installation over areceiving surface (not shown) in accordance with an embodiment. The noninfill artificial turf system 200 includes a sheet member 202 made of aflexible material. The sheet member 202 defines a first surface, orprimary backing 204 for interfacing with the receiving surface, and asecond surface 206. The non infill artificial turf system 200 furtherincludes a plurality of primary yarns 208 made of straight fibers(substantially straight fibers) which are upwardly extending from thesecond surface 206 of the sheet member 202 and a plurality of secondaryyarns 210 made of textured fibers or thatch fibers which are upwardlyextending from the second surface 206 of the sheet member 202. Becauseof their curly shape, the plurality of secondary yarns 210 positionthemselves automatically on the sheet member 202 in all direction andtherefore result in surrounding the plurality of primary yarns 208.

The plurality of secondary yarns 210 made of textured or thatch fibersrepresents more than 50% in weight of the plurality of primary andsecondary yarns 208, 210 taken together. More particularly, theplurality of secondary yarns 210 made of textured or thatch fibers mayrepresent one of: more than about 51%, more than about 55%, more thanabout 60%, more than about 65%, more than about 70%, more than about75%, more than about 80%, more than about 85%, more than about 90% andmore than about 95% in weight of the plurality of primary and secondaryyarns 208, 210 taken together.

The plurality of primary and secondary yarns 208, 210 which createstogether a carpet-like top layer 212 includes a series of regularlyspaced apart (or equally spaced) parallel rows of backstitches 214.These rows can be straight, in S or Z patterns, tufted or knitted.According to one embodiment, parallel rows of backstitches 214 ofprimary yarns 208 are alternated with parallel rows of backstitches of214 secondary yarns 210. According to another embodiment, the series ofregularly spaced apart parallel rows of backstitches 214 are made of aplurality of secondary yarns 210 surrounding or with at least one or aplurality of primary yarns 208. The combined yarn is therefore composedof both primary yarns 208 and secondary yarns 210. Regardless of theembodiment, the plurality of primary yarns 208 are thereforeinterspersed within the plurality of secondary yarns 210.

The fact that the non infill artificial turf system 200 combines boththe plurality of primary yarns 208 made of straight fibers and theplurality of secondary yarns 210 made of textured or thatch fibers (morethan 50% face weight of the plurality of secondary yarns is greater thanthe face weight of the plurality of primary yarns) provides improvedstraight fiber support, player traction and shock absorbentcharacteristics to the shock absorbent surface covering panel 200.

As shown in FIGS. 3-6, and as better shown in FIG. 6, the non infillartificial turf system 200 includes a plurality of backstitches 214 a.Each backstitch 214 a similarly includes a plurality of primary yarns208 made of straight fibers with a plurality of secondary yarns 210 madeof textured or thatch fibers, such as to allow the plurality ofsecondary yarns 210 made of textured or thatch fibers to represent morethan 50% in weight of the plurality of primary yarns 208 and secondaryyarns 210 taken together.

Each backstitch 214 a may be separated by a backstitch distance. Thebackstitch distance may range between 1/16″ and ½″.

The sheet member 202 or several sheet members used together may includematerials made of but not exclusively limited to Olefin (Polypropylene),Polyamide (Nylon), Polyethylene Terephalate (PET) virgin or a recyclablematerial, Polyestere Woven and non woven, cordura material either 100%or combination of these materials, manufactured in a closed-weave woven,an opened-weave woven, leno weave cross weave or non-woven materialsuitable to maximize ability to tuft, provide tuft bind of the primaryand secondary yarns, provide dimensional stability, thehardness-flexibility ratio of the sheet member, provide penetration ofthe sheet by the secondary coating which is applied to the bottom of thesheet member and which can be made of polyurethane or latex or acrylicor some other material suitable to ask as a binder to hold the fibers inplace to the sheet member or to allow the binding of the fibers to thesheet member by heat, pressure or with Polyurethane.

The thickness of the sheet member 202 is normally substantially uniformand may range between 0.20 mm to 2 mm.

The total mass (total of the mass of each filament) of each primary yarnfilament 208 may be in a range between 2,000 to 20,000 deniers. Thetotal mass of each primary yarn 208 may be in a range between 2,000 and20,000 deniers depending on the denier per filament (DPF) and number offilaments in the yarn. Preferably, the total mass of each primary yarnfilament 208 is ranged between 4,000 and 16,000 deniers.

The mass (total of the mass of each filament) of each secondary yarn 210may be in a range between 2,000 and 20,000 deniers. The mass of eachsecondary yarn 210 may be in a range between 2,000 and 20,000 deniersdepending on the denier per filament (DPF) and number of filaments inthe yarn. Preferably, the total mass of each secondary yarn filament 210is ranged between 4,000 and 16,000 deniers.

According to an embodiment, the mass of the secondary yarn filament 210is greater than the mass of the primary yarn filament 208. According toan embodiment, the mass of the primary yarns is between 2,000 and 19,999deniers and the mass of the secondary yarns is between 2,001 and 20,000deniers so long as the mass of the secondary yarn filament 210 isgreater than the mass of the primary yarn filament 208.

According to an embodiment, the mass of each secondary yarn 210 may bein a range between 15,001 and 20,000 deniers depending on the denier perfilament (DPF) and number of filaments in the yarn. Preferably, thetotal mass of each secondary yarn filament 210 is ranged between 15,001and 16,000 deniers.

The material of the plurality of primary yarns 208 may includepolyethylene, polypropylene, Polyamide, polyester (PET), Nylon, acombination of polyethylene and polypropylene and the like.

The shape and construction of the plurality of primary yarns 208 mayinclude flat face fibers, monofilament fibers, monotape yarn andfibrillated yarn, polyfilament fibers, parallel fibrillated orfibrillated fibers and split fibers. The primary yarns 208 may be madefrom extrusion and take different shapes such as a rectangularcross-section ribbon, diamond, horseshoe, U, V, S shape or a flatrectangular general cross section with its shorter sides rounded. Itscross-section may feature one or more curved-convex projections forinstance. When backstitched to the sheet member 202, the straight (orsubstantially straight) primary yarns 208 are set upwardly extendingfrom the second surface to simulate the blades of grass of natural grasscover.

The material of the plurality of secondary yarns 210 may includePolyamide, Polyester (PET), polyethylene, polypropylene, Nylon, acombination of polyethylene and polypropylene and the like.

The shape and construction of secondary yarns 210 may include texturizedmonofilament, monotape yarn and fibrillated yarn.

According to an embodiment, the physical characteristics of thesecondary yarns 210 are selected to obtain secondary yarns 210 that aremore rigid than the primary yarns 208, therefore having the secondaryyarns 210 providing the desired support while having the primary yarn208 providing the desired texture. These desired physicalcharacteristics may be commonly obtained through selection of a morerigid material for the secondary yarns 210 than for the primary yarns208; that is, the material of the primary yarns 208 (selected from thelist of materials disclosed herein for the primary yarns 208) is not thesame material as the material for the secondary yarns 210 (selected fromthe list of materials disclosed herein for the secondary yarns 210).Alternatively, a process (physical or chemical) over the secondary yarns210 modifying its physical characteristics may be used to obtain thedesired rigidity.

The plurality of secondary yarns 210, while described herein as texturedfibers or thatch fibers, may not require, according to one embodiment,to be textured. However, it is referred to herein as “textured” todistinguish itself in all embodiment from the primary “straight” yarn208. The secondary yarns 210 may be made of a plurality of filiformformations arranged in turfs so as to provide a better simulation of theblades of grass of natural grass cover. The manufacturing of secondaryyarns 210 to provide the desired shape and structure may be performed,for instance, by means of a heat, chemical or mechanical treatmentbefore use through which the secondary yarns 210 are crimped.Accordingly, second yarns 210 may consist of yarns of at least the samelength as the first yarns 208 that, when processed, result in thedesired shorter looking secondary yarns 210.

Still referring to FIGS. 3-6, and more particularly to FIG. 4, theelevation 218 of the primary yarns 208 from the second surface isillustrated as greater than the elevation 220 of the secondary yarns 210from the second surface regardless the real length of the primary andsecondary yarns 208 and 210. Thereby the secondary yarns 210 provide thedesired fiber support of the primary yarns 208, player traction andshock absorbing characteristics.

The tufting process of both primary and secondary yarns 208 and 210 canbe performed by stitching both the primary and secondary yarns 208 and210 concurrently, using the same needle. Alternatively, the primaryyarns 208 and secondary yarns 210 may be stitched separately, usingdistinct needles. The latter result in parallel backstitches of primaryyarns 208 and secondary yarns 210.

According to an embodiment, the tufting process includes threading theprimary and secondary yarns 208 and 210 through the sheet member 202.Loops are thereby formed. The tops of the loops are then cut leaving theprimary and secondary yarns 208 and 210 extending from the sheet member202 with the end of each of the primary and secondary yarns 208 and 210being cut.

It should be noted that while some prior art references, such as USApplication number 2004/0253390 by Trafford indicate that their bladesof different heights can be anchored into the pad in any manner desiredincluding any way shown in the references which are listed therein, aperson skilled in the art would know that the result that they wish toachieve is not possible by using the tufting techniques available atthat time. That is, all tufting techniques cited by references inTrafford will cut the blades at the same height. This point isillustrated clearly by another reference (US application number2003/0099787 by Fink) which states: “the typical machine available forsports carpet tufting is capable of cutting only one pile height”. It istherefore not possible to have straight blades of different heights anddifferent flexibility as in Trafford using conventional tuftingtechniques known at the time of Trafford which require the cutting ofthe loops resulting from the threading of yarn through a mat/sheetmember.

According to an embodiment, both the primary and secondary yarns 208 and210 are cut at the same height. The secondary yarns 210 beingpre-stressed, textured, crimped, curled, curved or otherwise pre-shaped,they will return to a shorter height to form the underturf 300 describedherein and leave the primary yarns 208 extending above the underturf 300thus higher than the secondary yarns 210.

According to another embodiment, the loops forming the rows of primaryyarns 208 and the loops forming the rows of secondary yarns 210 are cutusing blades which are set at different heights. The selection of theheights of the cutting blades for each row of yarn is determined basedon the desired rigidity and density for each of the rows.

According to another embodiment, the secondary yarns 210 are tufted inthe sheet member 202 forming loops which are cut at a given height. Theresulting carpet is then tufted again with primary yarns 208 formingloops which are cut at a given height which is different from the givenheight for the secondary yarns 210.

According to another embodiment, the primary yarns 208 are tufted in thesheet member 202 forming loops which are cut at a given height. Theresulting carpet is then tufted again with secondary yarns 210 formingloops which are cut at a given height which is different from the givenheight for the primary yarns 208.

According to an embodiment, the length of the secondary yarns 210 isgreater than the length of the primary yarns 208 while resulting in aheight of the secondary yarns 210 on the sheet member 202 which is lessthan the height of the primary yarns 208.

Depending the tufting configuration selected, the tufting gauge can varyfrom 3/16″ to ¾″.

The non infill artificial turf system 200 as described above mayincrease protection for child in playgrounds, may provide improvedplayers traction and shock absorbent characteristics for sport fields ofall kinds, and may reduce the surface temperature above the panel. Theplurality of secondary yarns 210 in sufficient quantity (more than 50%in weight) render the presence of rubber granules unnecessary to providestraight fiber support, while provide adequate traction for players andshock absorbent characteristics.

Referring back to FIGS. 2A-2B in comparison with FIGS. 4 and 5, the noninfill artificial turf system 200, the present realization featuresprimary yarns 208 backstitched to the sheet member 202 at locations,thereby defining through the backstitch interactions between the primaryyarns 208 and the sheet member 202 a plurality of primary backstitches302.

The secondary yarns 210 are also backstitched to the sheet member 202 atlocations, thereby defining a plurality of secondary backstitches 304.

Accordingly, the sheet member 202 is scattered with a plurality ofprimary backstitches 302 and secondary backstitches 304, thereby havingsecondary backstitches 304 located in the space around the primarybackstitches 302 or, in other words, having the secondary backstitches304 located in-between primary backstitches 302.

One should understand from the expression “scattered” and “locatedin-between” that the secondary backstitches 304 may be located in anylocation relative to the primary backstitches 302, from having thesecondary backstitches in rows aligned with rows of primary backstitches302 (see FIG. 6) to having the secondary backstitches in a plurality ofrows or random locations distributed between primary backstitches 302,with for example the rows of secondary backstitches 304 offsetlongitudinally and/or transversally relatively to the primarybackstitches 302 or relative to neighbor secondary backstitches 304.

Referring particularly to FIGS. 4 and 5, the secondary yarns 210 aremade of material having characteristics and shaped such as the secondaryyarns 210 extending from the secondary backstitches substantiallyslightly upward and mainly sideward in order for the secondary yarns 210as a whole to generate an underturf 300, or in other words a sub-layerof lower elevation (elevation 218) than the top elevation 220. Theunderturf 300, based on characteristics and/or shape of the secondaryyarns 210 defining the underturf 300, provides a support for the primaryyarns 208 under the lower elevation (elevation 218), thus about theprimary backstitches 302. Practically, the secondary yarns 210 providesside pressure over the lower portion (under elevation 218) of theprimary yarns 208 substantially on many (or all) directions of theprimary yarns 208 such as impeding or hindering the lower portion of theprimary yarns 208 to curve, bend or crook and thereby increase theefficient rigidity of the lower portion of the primary yarns 208 withoutrequiring changes in the material, characteristics or structure of theprimary yarns 208.

Further, to optimize the effect of the underturf 300, the secondaryyarns 210 are configured to extend in random directions from thesecondary backstitches 304 so as to intertwine with each other aroundand about the lower portion of the primary yarns 208, providing a“cushion” surrounding the primary backstitches 302 resulting in the“cushion” hindering deflection, curvature, bending and/or crooking ofthe lower portion of the primary yarns 208 as stated before.

Further, according to a realization, the secondary yarns 210 are curvedsuch as when backstitched to the sheet member 202 the secondary yarns210 raise from the secondary backstitches 304 and extend sideways inrandom directions to intertwine with each other. As a result, the lowersection of the primary yarns 208 is interspersed with the secondaryyarns 210 surrounding the primary yarns 208.

Further, according to a realization, the secondary yarns 210 intertwinewith each other to form a substantially homogeneous underturf 300,wherein homogeneous refers to performing as a “cushion” havingsubstantially similar characteristics over most of the surface of thesheet member 202.

Further, according to a realization, the secondary yarns 210 are morerigid than the primary yarns 208, wherein according to realizations, thesecondary yarns 210 being more rigid is performed through one ofselection of material for the primary yarns 208 and the secondary yarns210, the shape of the secondary yarns 210, and characteristicsassociated with the secondary yarns through one chemical processing andphysical processing of the secondary yarns 210.

Further, according to a realization, the weight of the plurality ofsecondary yarns 210 represents more than 50% of the weight of the sum ofthe plurality of primary yarns 208 and of the secondary yarnsbackstitched to a unit of sheet member 202.

Further, according to a realization, the length of secondary yarns 210(when forced in a straight configuration) is greater than the length ofprimary yarns 208 (when forced in a straight configuration).

Further, according to a realization, the ratio of secondary backstitches304 over the total number of backstitches (summing up primarybackstitches 302 and secondary backstitches 304) per unit of sheetmember 202 is at least 50%. According to a realization, this ratio is atgreater than 50%. According to a realization, this ratio is at leastgreater than 66%.

Further, according to a realization, the ratio of the number of yarnsper backstitch of the secondary backstitches over the primarybackstitches is at equal to 100%. According to a realization, this ratiois greater than 100%. According to a realization, this ratio is greaterthan about 125%.

The ratio of the lower elevation over the top elevation is smaller than75%. According to a realization, this ratio is smaller than 60%.According to a realization, this ratio is smaller than 50%. According toa realization, this ratio is smaller than 40%.

Further, according to a realization, the primary yarns 208 and thesecondary yarns 210 have respectively a color, and wherein the color ofthe primary yarns 208 differs from the color of the secondary yarns 210.For instance, the primary yarns 208 have a grass-green color while thesecondary yarns 210 have a color that includes some shade of brown tomore effectively recall a natural turf having a free grass on top anddying grass about the ground, with the layer of dying grass supportingthe free grass in a raised position.

Further, according to a realization, the primary yarns 208 and thesecondary yarns 210 have respectively a width, and wherein the width ofthe primary yarns 208 is greater than the width of the secondary yarns210.

Further, according to a realization, the primary yarns 208 and thesecondary yarns 210 have respectively a thickness, and wherein thethickness of the secondary yarns 210 is greater than the width of theprimary yarns 208, thereby improving the support the secondary yarns 210provide to the primary yarns 208.

In comparison, the non infilled artificial turf system 100 of FIGS. 2Aand 2B of the PRIOR ART features secondary yarns 110 extendingsubstantially upward from the sheet member 102 providing no support orlow support to the section of the primary yarns having an elevationsmaller than the elevation of the secondary yarns 108. Referringparticularly to FIG. 2A, the secondary yarns 110, regardless theirorientations, are not adapted to intertwine with each other to surroundthe primary yarns 108 and thereby provide support to the primary yarns108 and thus the “cushion” discussed before.

While preferred embodiments have been described above and illustrated inthe accompanying drawings, it will be evident to those skilled/in theart that modifications may be made without departing from thisdisclosure. Such modifications are considered as possible variantscomprised in the scope of the disclosure.

1. An artificial turf system for installation over a receiving surface,the artificial turf system comprising: a sheet member made of a flexiblematerial, the sheet member defining a first surface for interfacing withthe receiving surface and a second surface; primary yarns made ofstraight fibers backstitched in and threaded through the sheet memberand upwardly extending from the second surface of the sheet member to afirst elevation; and secondary yarns made of textured fibersbackstitched in and threaded through the sheet member and upwardlyextending from the second surface of the sheet member at a secondelevation less than the first elevation defining a difference inelevation which is caused by a difference in texture between the primaryyarns and the secondary yarns, wherein the secondary yarns are morerigid than the primary yarns, and wherein the primary yarns and thesecondary yarns have ends which are cut after being threaded through thesheet member.
 2. The artificial turf system of claim 1, wherein thematerial used for the primary yarns is not the same material which isused for the secondary yarns, wherein the material used for thesecondary yarns is more rigid than the material used for the primaryyarns.
 3. The artificial turf system of claim 1, wherein the secondaryyarns are textured, and wherein the textured fibers comprise crimpedfibers.
 4. The artificial turf system of claim 1, wherein the secondaryyarns represent more than 50% in weight of the primary and secondaryyarns together.
 5. The artificial turf system of claim 1, whereincombined yarns composed of the primary and secondary yarns arebackstitched in parallel equally spaced apart rows on the sheetmaterial.
 6. The artificial turf system of claim 1, wherein the mass ofthe secondary yarns is greater than the mass of the primary yarns. 7.The artificial turf system of claim 1, wherein the mass of the secondaryyarns is in a range between 15,001 and 20,000 deniers.
 8. The artificialturf system of claim 1, wherein the primary yarns and the secondaryyarns have respectively a length, and wherein the length of secondaryyarns is greater than the length of primary yarns.
 9. The artificialturf system of claim 1, wherein a ratio of the second elevation over thefirst elevation is smaller than 75%.
 10. An artificial turf system forinstallation over a receiving surface, the artificial turf systemcomprising: a sheet member made of a flexible material, the sheet memberdefining a first surface for interfacing with the receiving surface, anda second surface; a plurality of primary yarns being backstitched to thesheet member at primary backstitches, with the primary yarns raisingfrom the primary backstitches away from the second surface to a firstelevation; and a plurality of secondary yarns defining an underturf, thesecondary yarns being backstitched to the sheet member at secondarybackstitches, wherein the secondary backstitches are distributedin-between the primary backstitches, wherein the secondary yarns extendfrom the secondary backstitches up to a second elevation lower than thefirst elevation, wherein the secondary yarns extend sideways in randomdirections, and wherein the secondary yarns intertwine with othersecondary yarns.
 11. The artificial turf system of claim 10, wherein theprimary yarns comprise a lower section rising from the sheet memberunder the second elevation, and wherein the underturf provides a leastpartial support to the lower section of the primary yarns therebyimpeding the lower section of the primary yarns from curving, bending orcrooking.
 12. The artificial turf system of claim 10, wherein theprimary yarns are made of straight fibers.
 13. The artificial turfsystem of claim 10, wherein the secondary yarns are made of curvedfibers.
 14. The artificial turf system of claim 10, wherein theplurality of secondary yarns represents more than 50% in weight of thesum of the plurality of primary and secondary yarns together.
 15. Theartificial turf system of claim 10, wherein the secondary yarns are morerigid than the primary yarns.
 16. The artificial turf system of claim10, wherein the secondary yarns are textured, and wherein the texturedfibers comprise crimped fibers.
 17. The artificial turf system of claim10, wherein the primary yarns and the secondary yarns have respectivelya length, and wherein the length of secondary yarns is greater than thelength of primary yarns.
 18. The artificial turf system of claim 10,wherein a ratio of the second elevation over the first elevation issmaller than 75%.
 19. The artificial turf system of claim 10, whereinthe primary yarns and the secondary yarns have respectively a width, andwherein the width of the primary yarns is greater than the width of thesecondary yarns.
 20. The artificial turf system of claim 10, wherein theprimary yarns and the secondary yarns have respectively a thickness, andwherein the thickness of the secondary yarns is equal or greater thanthe width of the primary yarns.